Monodisperse,micron and submicron size aerosol generation with flow focusing.droplet size scaling laws,and device geometry.

摘要

Capill'ary flow focusing,or simply "flow focusing"(Ganan-Calvo 1998),has proven unique capabilities to generate neutrally charged,monodisperse liquid aerosol droplets.In most applications where the presence of electric charges is undesired,flow focusing has shown by far its superiority to electrospray,the only known atomisation technique comparable to flow focusing in terms of small droplet size and monodispersity,for two main reasons:first,the independency of the droplet size on the electrical properties of the liquid (which in most applications cannot be "tuned"to one's will),and last but not least,the extreme simplicity and robustness of flow focusing compared to electrospray.In this work,we report (i)the monodisperse aerosol generation in the micron-submicron range with flow focusing,(ii)the physical scaling laws for the droplet size and its geometrical standard deviation in terms of the Weber number for low Ohnesorge numbers,and (iii)the minimum droplet size attainable for a given device geometry (governed by the exit orifice diameter)and liquid properties.